add DWARF method to elf.File.

test both ELF and Mach-O in dwarf package.

R=r
DELTA=83  (44 added, 10 deleted, 29 changed)
OCL=34717
CL=34790

src/pkg/Make.deps

@@ -18,22 +18,23 @@ crypto/md5.install: hash.install os.install
 crypto/sha1.install: hash.install os.install
 datafmt.install: bytes.install container/vector.install fmt.install go/scanner.install go/token.install io.install os.install reflect.install runtime.install strconv.install strings.install
 debug/binary.install: io.install math.install os.install reflect.install
-debug/dwarf.install: debug/binary.install fmt.install os.install strconv.install
+debug/dwarf.install: debug/binary.install os.install strconv.install
-debug/elf.install: debug/binary.install fmt.install io.install os.install strconv.install
+debug/macho.install: bytes.install debug/binary.install debug/dwarf.install fmt.install io.install os.install strconv.install
-debug/gosym.install: debug/binary.install fmt.install io.install os.install strconv.install strings.install
+debug/elf.install: debug/binary.install debug/dwarf.install fmt.install io.install os.install strconv.install
+debug/gosym.install: debug/binary.install fmt.install os.install strconv.install strings.install
 debug/proc.install: container/vector.install fmt.install io.install os.install runtime.install strconv.install strings.install sync.install syscall.install
-ebnf.install: container/vector.install fmt.install go/scanner.install go/token.install os.install strconv.install strings.install unicode.install utf8.install
+ebnf.install: container/vector.install go/scanner.install go/token.install os.install strconv.install unicode.install utf8.install
 exec.install: os.install strings.install
-exvar.install: bytes.install fmt.install http.install io.install log.install strconv.install sync.install
+exvar.install: bytes.install fmt.install http.install log.install strconv.install sync.install
 flag.install: fmt.install os.install strconv.install
 fmt.install: io.install os.install reflect.install strconv.install utf8.install
 go/ast.install: go/token.install unicode.install utf8.install
-go/doc.install: container/vector.install fmt.install go/ast.install go/token.install io.install once.install regexp.install sort.install strings.install template.install
+go/doc.install: container/vector.install go/ast.install go/token.install io.install once.install regexp.install sort.install strings.install template.install
 go/parser.install: bytes.install container/vector.install fmt.install go/ast.install go/scanner.install go/token.install io.install os.install path.install strings.install
 go/printer.install: container/vector.install fmt.install go/ast.install go/token.install io.install os.install reflect.install strings.install tabwriter.install
 go/scanner.install: bytes.install container/vector.install fmt.install go/token.install io.install os.install sort.install strconv.install unicode.install utf8.install
 go/token.install: fmt.install strconv.install
-gob.install: bytes.install fmt.install io.install math.install os.install reflect.install strings.install sync.install unicode.install
+gob.install: bytes.install fmt.install io.install math.install os.install reflect.install sync.install
 hash.install: io.install
 hash/adler32.install: hash.install os.install
 hash/crc32.install: hash.install os.install
@@ -50,9 +51,9 @@ once.install: sync.install
 os.install: once.install syscall.install
 path.install: strings.install
 rand.install:
-reflect.install: runtime.install strconv.install strings.install
+reflect.install: runtime.install strconv.install
 regexp.install: bytes.install container/vector.install io.install os.install runtime.install utf8.install
-rpc.install: bufio.install fmt.install gob.install http.install io.install log.install net.install os.install reflect.install sort.install strconv.install strings.install sync.install template.install unicode.install utf8.install
+rpc.install: bufio.install fmt.install gob.install http.install io.install log.install net.install os.install reflect.install sort.install strings.install sync.install template.install unicode.install utf8.install
 runtime.install:
 sort.install:
 strconv.install: bytes.install math.install os.install unicode.install utf8.install

src/pkg/Makefile

@@ -33,6 +33,7 @@ DIRS=\
 	datafmt\
 	debug/binary\
 	debug/dwarf\
+	debug/macho\
 	debug/elf\
 	debug/gosym\
 	debug/proc\

src/pkg/debug/dwarf/testdata/typedef.c

@@ -3,7 +3,11 @@
 // license that can be found in the LICENSE file.
 
 /*
-gcc -gdwarf-2 -c typedef.c && gcc -gdwarf-2 -o typedef.elf typedef.o
+Linux ELF:
+gcc -gdwarf-2 -m64 -c typedef.c && gcc -gdwarf-2 -m64 -o typedef.elf typedef.o
+
+OS X Mach-O:
+gcc -gdwarf-2 -m64 -c typedef.c -o typedef.macho
 */
 
 typedef volatile int* t_ptr_volatile_int;

src/pkg/debug/dwarf/type.go

@@ -103,7 +103,7 @@ type ArrayType struct {
 	CommonType;
 	Type Type;
 	StrideBitSize int64;	// if > 0, number of bits to hold each element
-	Count int64;
+	Count int64;	// if == -1, an incomplete array, like char x[].
 }
 
 func (t *ArrayType) String() string {
@@ -111,8 +111,6 @@ func (t *ArrayType) String() string {
 }
 
 // A VoidType represents the C void type.
-// It is only used as the subtype for a pointer:
-// a FuncType that returns no value has a nil ReturnType.
 type VoidType struct {
 	CommonType;
 }
@@ -306,8 +304,8 @@ func (d *Data) Type(off Offset) (Type, os.Error) {
 	typeOf := func(e *Entry) Type {
 		toff, ok := e.Val(AttrType).(Offset);
 		if !ok {
-			err = DecodeError{"info", e.Offset, "missing type attribute"};
+			// It appears that no Type means "void".
-			return nil;
+			return new(VoidType);
 		}
 		var t Type;
 		if t, err = d.Type(toff); err != nil {
@@ -343,8 +341,7 @@ func (d *Data) Type(off Offset) (Type, os.Error) {
 			case TagSubrangeType:
 				max, ok := kid.Val(AttrUpperBound).(int64);
 				if !ok {
-					err = DecodeError{"info", kid.Offset, "missing upper bound"};
+					max = -2;	 // Count == -1, as in x[].
-					goto Error;
 				}
 				if ndim == 0 {
 					t.Count = max+1;
@@ -548,11 +545,9 @@ func (d *Data) Type(off Offset) (Type, os.Error) {
 		t := new(FuncType);
 		typ = t;
 		d.typeCache[off] = t;
-		if e.Val(AttrType) != nil {
 		if t.ReturnType = typeOf(e); err != nil {
 			goto Error;
 		}
-		}
 		t.ParamType = make([]Type, 0, 8);
 		for kid := next(); kid != nil; kid = next() {
 			var tkid Type;

src/pkg/debug/dwarf/type_test.go

@@ -2,10 +2,12 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package dwarf
+package dwarf_test
 
 import (
+	. "debug/dwarf";
 	"debug/elf";
+	"debug/macho";
 	"testing";
 )
 
@@ -33,29 +35,36 @@ func elfData(t *testing.T, name string) *Data {
 		t.Fatal(err);
 	}
 
-	dat := func(name string) []byte {
+	d, err := f.DWARF();
-		s := f.Section(".debug_" + name);
-		if s == nil {
-			return nil
-		}
-		b, err := s.Data();
 	if err != nil {
-			t.Fatal(".debug_"+name+":", err);
+		t.Fatal(err);
 	}
-		return b;
+	return d;
-	};
+}
 
-	d, err := New(dat("abbrev"), nil, nil, dat("info"), nil, nil, nil, dat("str"));
+func machoData(t *testing.T, name string) *Data {
+	f, err := macho.Open(name);
 	if err != nil {
-		t.Fatal("New:", err);
+		t.Fatal(err);
 	}
 
+	d, err := f.DWARF();
+	if err != nil {
+		t.Fatal(err);
+	}
 	return d;
 }
 
 
-func TestTypedefs(t *testing.T) {
+func TestTypedefsELF(t *testing.T) {
-	d := elfData(t, "testdata/typedef.elf");
+	testTypedefs(t, elfData(t, "testdata/typedef.elf"));
+}
+
+func TestTypedefsMachO(t *testing.T) {
+	testTypedefs(t, machoData(t, "testdata/typedef.macho"));
+}
+
+func testTypedefs(t *testing.T, d *Data) {
 	r := d.Reader();
 	seen := make(map[string]bool);
 	for {

src/pkg/debug/elf/file.go

@@ -7,6 +7,7 @@ package elf
 
 import (
 	"debug/binary";
+	"debug/dwarf";
 	"fmt";
 	"io";
 	"os";
@@ -330,3 +331,26 @@ func (f *File) Section(name string) *Section {
 	}
 	return nil;
 }
+
+func (f *File) DWARF() (*dwarf.Data, os.Error) {
+	// There are many other DWARF sections, but these
+	// are the required ones, and the debug/dwarf package
+	// does not use the others, so don't bother loading them.
+	var names = [...]string{"abbrev", "info", "str"};
+	var dat [len(names)][]byte;
+	for i, name := range names {
+		name = ".debug_" + name;
+		s := f.Section(name);
+		if s == nil {
+			continue;
+		}
+		b, err := s.Data();
+		if err != nil && uint64(len(b)) < s.Size {
+			return nil, err;
+		}
+		dat[i] = b;
+	}
+
+	abbrev, info, str := dat[0], dat[1], dat[2];
+	return dwarf.New(abbrev, nil, nil, info, nil, nil, nil, str);
+}